Sometimes you may need to attach a 2 dollar fee to a transaction to have any chance of getting it through. Others all you need is less than 200 sats. Knowing the difference is valuable I think.

Johoe's mempool size statistics is a really useful resource to understand exactly what's going on with the blockchain at any given time. It may look a bit daunting at first glance but it has all the tools you need to decide whether to send your transaction now or wait till things calm down a bit.

You can change the timespan the graph shows, so get an overview to see if the network is really busy and then zoom in to get a more detailed recent view. It stacks the fee rates on top of each other, distinguised by color, so you can see how likely each fee will be to succeed.

No need to write more here, there's an adequate description of what is being displayed, shown undeneath the graph.

It has saved me lots of fees over the years.